Glass fiber woven cloth impregnated pipe, its preparation method and composite insulator

Abstract

The application relates to a glass fiber woven cloth impregnated pipe and a preparation method and a composite insulator thereof, and belongs to the field of high-voltage electrical equipment manufacturing. The glass fiber woven cloth impregnated pipe is a fiber cloth reinforced resin material, and comprises a resin matrix and a fiber cloth reinforcing layer. The fiber cloth reinforcing layer comprises a bottom layer, a middle layer and an outer layer. The bottom layer is formed by overlapping and winding polyester fiber woven cloth or polyester surface felt. The middle layer is formed by overlapping and winding glass fiber woven cloth. The outer layer is formed by overlapping and winding polyester fiber woven cloth or polyester surface felt. The resin matrix is mainly formed by curing cyanate ester resin, E51 resin, E44 resin and a curing agent. The glass fiber woven cloth impregnated pipe is formed by impregnating fiber cloth with resin to form a fiber cloth reinforced resin material. The interface does not delaminate at high temperature, so that the high-temperature resistance and arc resistance are improved. Moreover, the polyester fiber cloth is resistant to SF6 gas and its decomposition products.

Description

Technical Field

[0001] This invention relates to a glass fiber braided cloth impregnated tube, its preparation method, and a composite insulator, belonging to the field of high-voltage electrical equipment manufacturing. Background Technology

[0002] Hollow composite insulators possess a range of superior electromechanical properties, including light weight, compact structure, and excellent resistance to pollution flashover, wet flashover, and explosion-proof performance, making them a preferred choice in the power industry compared to porcelain insulators. With the maturation of composite insulator manufacturing technology and the increasing demand for composite external insulation in DC circuit breakers, hollow composite insulators are no longer limited to their use as external insulation for incoming and outgoing lines in substation power equipment; they are increasingly being used as external insulation for the arc-extinguishing chambers of open switchgear. Conventional hollow composite insulators typically use E51 resin as the matrix for their glass fiber wound tubes, impregnated with glass fiber, and formed using a wet winding process. The material's high-temperature resistance is generally average. During circuit breaker breaking, discrete electric arcs or high-temperature gas flows can erode the inner wall of the hollow composite insulator, leading to gradual material deterioration, a gradual decrease in insulation and mechanical properties, and ultimately, insulation or mechanical failure of components. Currently, domestic insulator manufacturers have made numerous attempts to improve the arc resistance of the inner wall of hollow composite insulators.

[0003] For example, Chinese utility model patent CN201181616Y discloses a method to improve the arc resistance of the inner wall of a hollow composite insulator by adding an epoxy ester insulating varnish layer. However, in actual use, the bonding force between the inner lining layer and the substrate is weak, and the epoxy ester insulating varnish layer is prone to peeling at high temperatures. Chinese utility model patent CN210378624U discloses a hollow composite insulator using epoxy resin glass fiber as the inner tube, but it does not provide a specific and clear description of the arc-resistant inner lining. Chinese invention patent application CN109786047A and Chinese utility model patent CN209418219U disclose a hollow composite insulator and circuit breaker using polytetrafluoroethylene (PTFE) as the inner lining. The inner lining is cylindrical, and an epoxy resin-glass fiber wound composite tube is assembled on the outside of the inner lining. The gap between the two is coated with a thick adhesive layer. Chinese utility model patent CN206672726U discloses a composite insulator made by winding an epoxy resin-glass fiber layer around the outside of a PTFE hollow tube. Using PTFE tubing as the inner lining is a feasible method, but the manufacturing process is complex and costly. Furthermore, the thermal expansion coefficients of PTFE, the epoxy resin-glass fiber wound tube, and the adhesive layer differ, which can easily lead to delamination at the interfaces under high temperatures. Under high voltage conditions, this can cause breakdown along two interfaces, thus posing a threat to the safe and reliable operation of the switchgear. Summary of the Invention

[0004] The purpose of this invention is to provide a glass fiber braided fabric impregnated tube that solves the problems of poor temperature resistance, insulation performance, and mechanical properties at high temperatures in the prior art.

[0005] The second objective of this invention is to provide a method for preparing glass fiber braided fabric impregnated tubes, thereby solving the problem of complex manufacturing processes in the prior art.

[0006] The third objective of this invention is to provide a composite insulator that solves the problems of poor arc resistance and easy delamination at high temperatures in the prior art.

[0007] To achieve the above objectives, the technical solution adopted by the glass fiber braided fabric impregnated tube of the present invention is as follows:

[0008] A glass fiber woven fabric impregnated tube, wherein the impregnated tube is a fiber cloth reinforced resin material, comprising a resin matrix and a fiber cloth reinforcing layer; the fiber cloth reinforcing layer comprises a bottom layer, an intermediate layer and an outer layer, wherein the bottom layer is formed by overlapping and winding polyester fiber woven fabric or polyester surface felt, the intermediate layer is formed by overlapping and winding glass fiber woven fabric, and the outer layer is formed by overlapping and winding polyester fiber woven fabric or polyester surface felt; the resin matrix is ​​mainly formed by curing cyanate ester resin, E51 resin, E44 resin and a curing agent.

[0009] The glass fiber woven fabric impregnated tube of the present invention is formed by impregnating fiber cloth with resin to form a fiber cloth reinforced resin material, so that the impregnated tube has no obvious interface layer and will not delaminate at high temperature, thereby improving its high temperature resistance and arc resistance. Moreover, the polyester fiber cloth is resistant to SF6 gas and its decomposition products.

[0010] More preferably, the glass fiber woven fabric is a glass fiber warp-woven fabric, and the fiber direction of the glass fiber warp-woven fabric is one or more combinations of uniaxial, biaxial, triaxial, and tetraaxial.

[0011] Preferably, the resin matrix in the glass fiber woven fabric impregnated tube has a mass fraction of 60-80%.

[0012] Preferably, the thickness ratio of the bottom layer, middle layer and outer layer of the fiber cloth reinforcement layer is (1-2):(8.4-14):(1-2).

[0013] Preferably, the number of winding layers in the bottom layer is 2 to 4.

[0014] Preferably, the outer layer has 2 to 4 winding layers.

[0015] More preferably, the mass ratio of cyanate ester resin, E51 resin, E44 resin and curing agent is (50-60):(100-110):(10-15):(80-85).

[0016] The technical solution adopted in the preparation method of the glass fiber braided fabric impregnated tube of the present invention is as follows:

[0017] A method for preparing a glass fiber braided fabric impregnated tube includes the following steps:

[0018] (1) Pre-bake the mold core and mold sleeve;

[0019] (2) Roll the pre-baked mold core sequentially with the bottom layer, middle layer and outer layer;

[0020] (3) Place the pre-made mold core into the pre-baked mold cavity and assemble the mold for further pre-baking;

[0021] (4) Mix the cyanate ester resin, E51 resin, E44 resin and curing agent, and vacuum them to obtain the resin compound;

[0022] (5) Vacuum the pre-baked mold, then inject the resin material obtained in step (4) into the mold cavity, and after curing, cooling and demolding, obtain the glass fiber woven fabric impregnated tube.

[0023] The method for preparing the glass fiber woven fabric impregnated tube of the present invention involves sequentially rolling pre-made polyester fiber woven fabric and / or surface mat, glass fiber woven fabric and polyester fiber woven fabric and / or surface mat as reinforcing layers, and using a vacuum impregnation process to impregnate the reinforcing layers with resin to form a glass fiber reinforced impregnated tube. This product has good high temperature resistance and arc resistance, and the method is simple to operate and easy to mass-produce in factories.

[0024] Preferably, the roll is prefabricated in an overlapping manner.

[0025] In order to make the mixture of the substances more uniform, preferably, the mixing in step (4) is a segmented stirring mixing; the segmented stirring is two-stage stirring, with the stirring speed of the first stage being 10r / min to 15r / min and the stirring speed of the second stage being 30r / min to 40r / min.

[0026] Preferably, the first stage of stirring takes 0.5 to 1 hour; the second stage of stirring takes 0.2 to 0.5 hours.

[0027] To improve curing efficiency, preferably, the curing temperature in step (5) is 60-130°C and the curing time is 10-21 hours.

[0028] More preferably, the curing is a multi-stage curing process.

[0029] More preferably, the multi-stage curing is a four-stage curing, wherein the temperature of the first stage is 60-70℃, the temperature of the second stage is 80-100℃, the temperature of the third stage is 110-120℃, and the temperature of the fourth stage is 120-130℃.

[0030] More preferably, the heating rate between each section is 1℃ / min.

[0031] More preferably, the curing time for the first stage is 1-3 hours, the curing time for the second stage is 1-3 hours, the curing time for the third stage is 5-10 hours, and the curing time for the fourth stage is 3-5 hours.

[0032] Preferably, in step (5), the resin material obtained in step (4) is injected into the mold cavity at a rate of 150-300 g / min.

[0033] More preferably, the injection is stopped when resin material appears at the riser at the other end of the mold.

[0034] Preferably, the pre-baking temperature in steps (1) and (3) is 100-120°C.

[0035] More preferably, the pre-drying time in step (1) is 1 to 3 hours; the continued pre-drying time in step (3) is 2 to 4 hours.

[0036] The technical solution adopted by the composite insulator of the present invention is as follows:

[0037] A composite insulator includes the aforementioned glass fiber braided fabric vacuum impregnation tube, an insulating umbrella sleeve disposed around the outer periphery of the impregnation tube, and connectors disposed at both ends of the impregnation tube.

[0038] The composite insulator of the present invention utilizes the high temperature resistance of cyanate ester resin material to improve the high temperature resistance and arc burning resistance of the inner wall of the insulating tube. Moreover, the resin and the substrate are evenly distributed, and the expansion of each part tends to be consistent under high temperature conditions, making it less prone to delamination defects. Attached Figure Description

[0039] Figure 1 The glass fiber woven fabric impregnated tube is an embodiment of the present invention;

[0040] Figure 2 The composite insulator is an embodiment of the present invention;

[0041] Among them, 1 is a fiberglass woven fabric impregnated tube, 2 is an umbrella skirt sheath, and 3 is a connecting accessory. Detailed Implementation

[0042] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0043] I. Specific embodiments of the glass fiber woven fabric impregnated tube and its preparation method of the present invention are as follows:

[0044] Example 1

[0045] The method for preparing the glass fiber braided fabric impregnated tube in this embodiment includes the following steps:

[0046] (1) Mold pretreatment

[0047] a. Clean the mold core and mold cavity of the glass fiber woven fabric vacuum impregnation tube using a scraper, lint-free paper and alcohol, remove impurities such as grease and foreign matter, and evenly coat the surface of the mold core and mold cavity with release agent;

[0048] b. Place the mold core and mold sleeve in an oven for pre-baking at around 100℃ for 3 hours.

[0049] (2) Prefabrication of glass fiber woven fabric roll

[0050] a. The fiberglass woven fabric is made of fiberglass warp-woven fabric with biaxial fiber direction;

[0051] b. Take the pre-dried mold core out of the oven and first wind two layers of polyester fiber woven fabric or surface felt resistant to SF6 gas and its decomposition products onto it; then wind the glass fiber warp-woven fabric in layers by overlapping, with a final thickness of 10mm; continue to wind two layers of polyester surface felt by overlapping; after the winding is completed, use glass fiber yarn to tie the fabric roll in sections to prevent the fabric roll from loosening.

[0052] c. Place the pre-made fabric roll into the mold cavity, assemble the mold, and then put it into the oven for pre-drying at a temperature of about 100℃ for 4 hours.

[0053] (3) Preparation of vacuum impregnated tubes made of glass fiber woven fabric

[0054] a. The high-temperature resistant resin compound is composed of cyanate ester resin (BADCy), E51 resin, E44 resin, curing agent HY918 and accelerator DF-602, and is thoroughly mixed in stages and vacuum degassed in a mixing tank at 50℃ at a mass ratio of 60:100:10:80:0.2. The first stage is a stirring speed of 10 r / min for 1 hour; the second stage is a stirring speed of 30 r / min, and vacuum degassed at the same time. When the vacuum degree is less than 100 Pa, stirring is continued for 0.5 hours and then stopped.

[0055] b. Remove the mold from the oven, connect it to the glue injection system, and evacuate the mold for more than 0.5 hours until the vacuum level stabilizes;

[0056] c. Open the dry compressed gas valve to pressurize the mixing tank, and control the pressure at 0.02MPa; the compressed gas is dry compressed air;

[0057] d. Open the injection valve and inject glue into the mold cavity at a speed of 150g / min. Stop injecting glue when glue appears at the riser at the other end of the mold.

[0058] e. Place the mold after glue injection into an oven for curing; adopt a multi-stage curing process: stage 1 temperature 60℃, time 3h, stage 2 temperature 80℃, time 3h, stage 3 temperature 110℃, time 10h, stage 4 temperature 120℃, time 5h, with a heating rate of 1℃ / min between each stage.

[0059] f. After curing, close the oven and let it cool to between 40 and 60°C. Remove the mold and demold, then place it at room temperature. Machining is then performed according to the size requirements of the impregnation tube.

[0060] The glass fiber woven fabric impregnated tube prepared by the method of this embodiment has the following structure: it includes a fiber cloth and a resin impregnated on the fiber cloth, wherein the fiber cloth includes a bottom layer of overlapping material, polyester fiber woven fabric or surface mat, a middle layer of overlapping material, glass fiber woven fabric, and an outer layer of overlapping material, polyester fiber woven fabric or surface mat. The corresponding parameters can be determined by the parameters corresponding to the preparation method of Example 1.

[0061] Example 2

[0062] The method for preparing the glass fiber braided fabric impregnated tube in this embodiment includes the following steps:

[0063] (1) Mold pretreatment

[0064] a. Clean the mold core and mold cavity of the glass fiber woven fabric vacuum impregnation tube using a scraper, lint-free paper and alcohol, remove impurities such as grease and foreign matter, and evenly coat the surface of the mold core and mold cavity with release agent;

[0065] b. Place the mold core and mold sleeve in an oven for pre-drying at a temperature of about 120℃ for 1 hour.

[0066] (2) Prefabrication of glass fiber woven fabric roll

[0067] a. The fiberglass woven fabric is made of warp-woven fiberglass with a triaxial fiber orientation;

[0068] b. Take the pre-dried mold core out of the oven and first wind 4 layers of polyester fiber woven fabric or surface felt resistant to SF6 gas and its decomposition products onto it; then wind the glass fiber warp-woven fabric in layers by overlapping, with a final thickness of 14mm; continue to wind 4 layers of polyester surface felt by overlapping; after the winding is completed, use glass fiber yarn to tie the fabric roll in sections to prevent the fabric roll from loosening.

[0069] c. Place the pre-made fabric roll into the mold cavity, assemble the mold, and then put it into the oven for pre-drying at a temperature of about 120℃ for 2 hours.

[0070] (3) Preparation of vacuum impregnated tubes made of glass fiber woven fabric

[0071] a. The high-temperature resistant resin compound is composed of cyanate ester resin (BADCy), E51 resin, E44 resin, curing agent HY918 and accelerator DF-602. It is mixed in stages at a mass ratio of 60:100:10:80:0.2 in a mixing tank at 60℃, and then vacuum degassed. The first stage is a stirring speed of 15 r / min for 0.5 h. The second stage is a stirring speed of 40 r / min, and vacuum degassed at the same time. When the vacuum degree is less than 100 Pa, stirring is continued for 0.2 h and then stopped.

[0072] b. Remove the mold from the oven, connect it to the glue injection system, and evacuate the mold for more than 0.5 hours until the vacuum level stabilizes;

[0073] c. Open the drying compressed gas valve to pressurize the mixing tank, controlling the pressure at 0.04 MPa; the compressed gas is nitrogen.

[0074] d. Open the injection valve and inject glue into the mold cavity at a speed of 300g / min. Stop injecting glue when glue appears at the riser at the other end of the mold.

[0075] e. Place the mold after glue injection into an oven for curing; adopt a multi-stage curing process: stage 1 temperature 70℃, time 1h, stage 2 temperature 100℃, time 1h, stage 3 temperature 120℃, time 5h, stage 4 temperature 130℃, time 3h, with a heating rate of 1℃ / min between each stage.

[0076] f. After curing, close the oven and let it cool to between 40 and 60°C. Remove the mold and demold, then place it at room temperature. Machining is then performed according to the size requirements of the impregnation tube.

[0077] In other embodiments, the fiber orientation of the glass fiber woven fabric can also be uniaxial or tetraaxial.

[0078] The glass fiber woven fabric impregnated tube prepared by the method of this embodiment has the following structure: it includes a fiber cloth and a resin impregnated on the fiber cloth, wherein the fiber cloth includes a bottom layer of overlapping material, polyester fiber woven fabric or surface mat, a middle layer of overlapping material, glass fiber woven fabric, and an outer layer of overlapping material, polyester fiber woven fabric or surface mat. The corresponding parameters can be determined by the parameters corresponding to the preparation method of Example 1.

[0079] Example 3

[0080] The glass fiber braided fabric impregnated tube in this embodiment is prepared according to the method in Example 1.

[0081] The glass fiber woven fabric impregnated tube prepared by the method of this embodiment has the following structure: it includes a fiber cloth and a resin impregnated on the fiber cloth. The fiber cloth includes a bottom layer of polyester fiber woven fabric or surface mat, a middle layer of glass fiber woven fabric, and an outer layer of polyester fiber woven fabric or surface mat. The resin includes cyanate ester resin (BADCy), E51 resin, E44 resin, curing agent HY918, and accelerator DF-602. The mass fraction of the resin in the glass fiber woven fabric impregnated tube is 70%, and the mass ratio of cyanate ester resin, E51 resin, E44 resin, curing agent, and accelerator is 50:100:10:80:0.2. The inner and outer polyester fiber woven fabrics or surface mats are overlapped by 4 layers, i.e., the thickness is 2 mm. The middle glass fiber woven fabric is overlapped by 21 layers, with a thickness of 8.4 mm. The results are as follows. Figure 1 As shown.

[0082] II. Specific embodiments of the composite insulator of the present invention are as follows:

[0083] Example 4

[0084] The composite insulator of this embodiment is prepared using the following steps: A silicone rubber shed sheath 2 is formed on the outer layer of the glass fiber woven fabric vacuum impregnation tube 1 prepared in Example 3 using injection molding; then, attachments 3 are glued to both ends. The result is as follows: Figure 2 As shown.

[0085] III. Comparison of Arc Resistance in Experimental Examples

[0086] The arc resistance performance was tested on an arc resistance testing machine according to the test method of the national standard GB / T1141-2002 "Test for dry solid insulating materials against high voltage and low current arc discharge". The test results are as follows:

[0087] Table 1

[0088] product Standard products Example 1 Example 2 Example 3 Time, s 210 368 394 316

[0089] Conventional products are composite insulators made by winding an epoxy resin glass fiber layer around the outside of a hollow polytetrafluoroethylene tube. As shown in Table 1, compared with conventional products, the glass fiber braided impregnated tube prepared in this invention has a longer arc resistance time and better arc resistance.

Claims

1. A glass fiber braided cloth impregnated tube for composite insulators, characterized in that, The impregnated tube is made of fiber cloth reinforced resin material, including a resin matrix and a fiber cloth reinforcing layer; the fiber cloth reinforcing layer includes a bottom layer, an intermediate layer and an outer layer, the bottom layer is formed by overlapping and winding polyester fiber woven fabric or polyester surface felt, the intermediate layer is formed by overlapping and winding glass fiber woven fabric, and the outer layer is formed by overlapping and winding polyester fiber woven fabric or polyester surface felt; the resin matrix is ​​mainly formed by curing cyanate ester resin, E51 resin, E44 resin and curing agent; the mass fraction of the resin matrix in the glass fiber woven fabric impregnated tube is 60~80%; the mass ratio of cyanate ester resin, E51 resin, E44 resin and curing agent is (50~60):(100~110):(10~15):(80~85).

2. The glass fiber braided cloth impregnated tube for composite insulators according to claim 1, characterized in that, The thickness ratio of the bottom, middle and outer layers of the fiber cloth reinforcement layer is (1~2):(8.4~14):(1~2).

3. The glass fiber braided cloth impregnated tube for composite insulators according to claim 2, characterized in that, The number of winding layers in the bottom layer is 2 to 4.

4. The glass fiber braided cloth impregnated tube for composite insulators according to claim 2, characterized in that, The outer layer has 2 to 4 winding layers.

5. A method for preparing a glass fiber braided fabric impregnated tube for composite insulators as described in claim 1, characterized in that, Includes the following steps: (1) Pre-bake the mold core and mold sleeve; (2) Roll the pre-baked mold core sequentially with the bottom layer, middle layer and outer layer; (3) Place the pre-made mold core into the pre-baked mold cavity and assemble the mold for further pre-baking; (4) Mix the cyanate ester resin, E51 resin, E44 resin and curing agent, and vacuum them to obtain the resin compound; (5) Vacuum the pre-baked mold, then inject the resin material obtained in step (4) into the mold cavity, and after curing, cooling and demolding, obtain the glass fiber woven fabric impregnated tube.

6. The method for preparing the glass fiber braided cloth impregnated tube for composite insulators according to claim 5, characterized in that, The curing temperature in step (5) is 60-130℃; the curing time is 10-21h.

7. The method for preparing the glass fiber braided cloth impregnated tube for composite insulators according to claim 5, characterized in that, The pre-baking temperature in steps (1) and (3) is 100~120℃.

8. A composite insulator, characterized in that, It includes the glass fiber braided cloth impregnation tube as described in any one of claims 1 to 4, the insulating umbrella sleeve disposed on the outer periphery of the impregnation tube, and the connectors disposed at both ends of the impregnation tube.

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